September 16 is designated as the International Day for the Preservation of the Ozone Layer by the United Nations to protect the fragile shield of the Ozone layer, which protects the planet Earth from the harmful ultraviolet radiations from the Sun. India has been celebrating this day since 1995. The theme for this year is \u201cMontreal Protocol: Advancing Climate Actions\u201d.<\/em><\/p>\n Ozone (O3) is a reactive gas, consisting of three oxygen atoms which can be natural or man-made and found in the Earth\u2019s high atmosphere (stratosphere). The word \u2018ozone hole\u2019\u00a0<\/strong>refers to areas or regions harmed by damaging UV radiations.<\/p>\n The ozone present in the stratosphere, at a height of around 15 to 30 km is produced naturally by the interaction of solar ultraviolet light with molecular oxygen (O2). On the other hand the tropospheric or ground-level ozone is principally produced by photochemical processes that involve volatile organic compounds (VOC) and nitrogen oxides.<\/p>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n (Text source: http:\/\/www.noaa.gov)<\/p><\/div>\n The ozone layer is depleted in both hemispheres of the Earth, specifically Antarctica in the Southern Hemisphere and the Arctic in the Northern Hemisphere. However, the phenomenon is more\u00a0<\/span>recognised<\/span>\u00a0in Antarctica than in the Arctic.<\/span><\/p>\n The mechanism of the ozone hole is intimately related to the temperature of the stratosphere. If the temperature goes below -78 degrees Celsius, stratospheric clouds form, worsening the status of the ozone hole.<\/span><\/p>\n The<\/span>\u00a0extent of the ozone hole above Antarctica<\/span><\/a>\u00a0varies each year, beginning in August and closing in November or December.<\/span><\/p>\n Some consumer goods and industrial activities release\u00a0\u201chalogen source gases\u201d<\/strong>\u00a0into the atmosphere. The ozone layer is weakened by these gases bringing chlorine and bromine into the stratosphere. For instance, practically all air conditioning and refrigeration systems contain chlorofluorocarbons, eventually making their way to the stratosphere where they break down to produce chlorine atoms that deplete the ozone layer.<\/span><\/p>\n Halons, used in fire extinguishers contain ozone-depleting bromine atoms. Here comes the important role of the Montreal Protocol \u2014\u00a0 governing the global production and consumption of all primary halogen source gases resulting from human activity.<\/span><\/p>\n Exposure to UltraViolet B (UVB) rays has various effects on:<\/p>\n A. Human Health:<\/strong>\u00a0The depletion of the ozone layer has resulted in low amounts of ozone, which means reduced protection from the sun\u2019s rays and increased exposure to UVB radiation at the Earth\u2019s surface. Laboratory and epidemiological research show that UVB induces non-melanoma skin\u00a0cancer<\/a>\u00a0and plays an important role in malignant melanoma formation. UVB has also been related to the development of cataracts, which are cloudy lenses in the eyes.<\/p>\n B. Flora Life:<\/strong>\u00a0UVB radiation affects the plants \u2014 both physiologicaly and in their development processes. The growth of trees is affected directly and indirectly by the UVB radiation. For instance, nutrient distribution and developmental phase are indirectly affected.<\/p>\n C. Marine Life:<\/strong>\u00a0Phytoplankton production is limited to the euphotic zone, the upper layer of the water column that receives enough sunshine to support net productivity. Solar UVB radiation has been proven to influence phytoplankton orientation and motility, resulting in lower survival rates. Small increases in UVB radiation can cause population declines in small marine organisms, having repercussions for the entire marine food chain.<\/p>\n D. Terrestrial Life:<\/strong>\u00a0Increased UVB radiation can have an impact on terrestrial biogeochemical cycles, affecting both sources and sinks of greenhouse gases and chemically significant trace gases such as carbon dioxide and carbon monoxide.<\/p>\n Adopted on September 16, 1987, the Montreal Protocol is the landmark multilateral environmental agreement that regulates the production and consumption of man-made chemicals referred to as ozone-depleting substances (ODS). The stratospheric ozone layer is damaged by these ODS.<\/p>\n According to the UNEP website,<\/p>\n the Montreal Protocol phases down the consumption and production of the different ODS step-wise, with different timetables for developed and developing countries. Under the treaty, all parties have specific responsibilities related to the phase-out of the various groups of ODS, control of ODS trade, annual reporting of data, national licensing systems to check the imports and exports of ODS and other matters.<\/p><\/blockquote>\n There are different responsibilities for developing and developed countries, but the countries have binding, time-targeted, and measurable commitments.<\/p>\n Implementation of the Montreal Protocol<\/strong><\/p>\n Hydrochlorofluorocarbons (HCFCs) are used for different purposes such as refrigeration, air conditioning, and foam applications. However, they were phased out under the Montreal Protocol due to their ozone layer depleting effects. These are considered ODS and powerful greenhouse gases. The most commonly found HCFC has a global warming potential (GWP) around 2,000 times that of CO2. The parties agreed in 2007 to phase out HCFCs to maintain the climate of the Earth.<\/p>\n Universal ratification<\/strong><\/p>\n On September 16, 2009, the Vienna Convention and the Montreal Protocol became the first treaties in United Nations history to be universally ratified.<\/p>\n Do you know:<\/strong>\u00a0The Vienna Convention was the first treaty of any kind to be signed by all participating countries, taking effect in 1988 and being universally ratified in 2009.<\/em><\/p>\n The Kigali Amendment<\/strong><\/p>\n Hydrofluorocarbons (HFCs) are a distinct family of compounds that were developed to help with the timely phase-out of CFCs and HCFCs as non-ozone-depleting alternatives. Nowadays, HFCs are often found in refrigerators, air conditioners, foams, aerosols, and other products. These substances are safe for the stratosphere\u2019s ozone layer, however, they have high global warming potentials (GWPs) of around 12000-14,000.<\/p>\n The Parties to the Montreal Protocol voted to phase down HFCs at their 28th Meeting of the Parties, held on October 15, 2016, in Kigali, Rwanda. HFCs were added to the list of compounds under international control, and a plan to gradually reduce them by 80-85% by the late 2040s was approved.<\/p>\nFirst thing first, let\u2019s know about \u2018Ozone\u2019<\/em><\/h4>\n
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<\/p>\nSo how is ozone layer depleted<\/i><\/h4>\n
Above all, why is ozone depletion harmful<\/strong><\/em><\/h4>\n
By the way, do you know what the Montreal Protocol is exactly<\/strong><\/em><\/h4>\n
Wondering how much the situation has improved now<\/em><\/strong><\/h4>\n
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